The present invention is generally directed to a flushing mechanism and, in particular, to a flushing mechanism using a phase change fluid adapted for use in toilet flushing applications which uses less water during each flushing cycle than in conventional toilet flushing mechanisms and which provides superior flushing characteristics.
Conventional flushing mechanisms used in toilet flushing operations generally use one of two different approaches to remove waste material from the toilet bowl. In a first approach, siphoning action is utilized to create a vacuum which draws bowl water and waste into the drain line and refills the bowl with fresh water. In a second approach which is typically used in household applications, a tank on the toilet bowl holds a predetermined amount of water which, when released, generates a high velocity flow to carry bowl water and waste into the drain line and refill the bowl with fresh water. The second approach relies on the weight of the water due to gravity to flush and replenish the bowl.
Since the weight of the water alone is utilized to flush and replenish the bowl, conventional toilets using this conventional system require about 14 to 16 liters of water during each flushing operation. Because of the concern for water conservation in general and the ever increasing passage of legislation requiring reduced water consumption in toilet flushing operations, it has become imperative that appropriate flushing mechanisms be developed and implemented to insure reduced water consumption during such toilet flushing operations However, it is also important that such new flushing devices be adaptable for use in existing tank-type toilets.
An attempt has been made to reduce water consumption by increasing the pressure provided by the water in the toilet tank. One such system is shown in U.S. Pat. Nos. 3,677,294 and 3,817,279. The systems disclosed in these patents utilize a pressure storage vessel, initially containing air at atmospheric pressure, which is filled with water at an elevated pressure thereby compressing the air in the tank. During the flush cycle, the air expands rapidly, exerting an additional force on the stored water thereby driving the stored water through the bowl at high velocity. Through the use of a such a system, less water is generally required during each flushing operation.
Systems such as those described in the above-cited U.S. patents have proven less than completely satisfactory for two reasons. First, since the internal volume of the pressure storage vessel must be sufficient to contain both the water required for the flush and compressed air, the vessel must be oversized, thereby requiring a larger water tank than is found on conventional toilets. Second, since the potential energy of the stored water is a function of inlet water line pressure, flushing performance will decrease at pressures substantially below the design pressure of the system.
The present inventors have developed several new flushing mechanisms including one using a phase change fluid and hydraulic actuation therefor which overcome the disadvantages inherent in the prior art. Accordingly, it is desired to provide an improved flush system adapted for toilet flushing operations which uses substantially less water than used by conventional systems and which provides excellent flushing properties.